Make it so that chrome.bookmarks.update can update the URL of a bookmark....

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "unprivileged": true,
     "types": [
       {
         "id": "MessageSender",
         "type": "object",
         "description": "An object containing information about the script context that sent a message or request.",
         "properties": {
@@ skipping 1497 matching lines @@
             "optional": true,
             "parameters": [
               {"name": "result", "$ref": "BookmarkTreeNode" }
             ]
           }
         ]
       },
       {
         "name": "update",
         "type": "function",
-        "description": "Updates the properties of a bookmark or folder. Specify only the properties that you want to change; unspecified properties will be left unchanged.  <b>Note:</b> Currently, only 'title' is supported.",
+        "description": "Updates the properties of a bookmark or folder. Specify only the properties that you want to change; unspecified properties will be left unchanged.  <b>Note:</b> Currently, only 'title' and 'url' are supported.",
         "parameters": [
           {"type": "string", "name": "id"},
           {
             "type": "object",
             "name": "changes",
             "properties": {
-              "title": {"type": "string", "optional": true}
+              "title": {"type": "string", "optional": true},
+              "url": {"type": "string", "optional": true}
             }
           },
           {
             "type": "function",
             "name": "callback",
             "optional": true,
             "parameters": [
               {"name": "result", "$ref": "BookmarkTreeNode" }
             ]
           }
@@ skipping 43 matching lines @@
             "properties": {
               "parentId": { "type": "string" },
               "index": { "type": "integer" }
             }
           }
         ]
       },
       {
         "name": "onChanged",
         "type": "function",
-        "description": "Fired when a bookmark or folder changes.  <b>Note:</b> Currently, only title changes trigger this.",
+        "description": "Fired when a bookmark or folder changes.  <b>Note:</b> Currently, only title and url changes changes trigger this.",
         "parameters": [
           {"type": "string", "name": "id"},
           {
             "type": "object",
             "name": "changeInfo",
             "properties": {
-              "title": { "type": "string" }
+              "title": {"type": "string"},
+              "url": {"type": "string", "optional": true}
             }
           }
         ]
       },
       {
         "name": "onMoved",
         "type": "function",
         "description": "Fired when a bookmark or folder is moved to a different parent folder.",
         "parameters": [
           {"type": "string", "name": "id"},
@@ skipping 562 matching lines @@
         "type": "function",
         "description": "Logs a message during internal unit testing.",
         "parameters": [
           {"type": "string", "name": "message"}
         ]
       }
     ],
     "events": []
   }
 ]